muni just posted a .pdf of a dharma talk given by Dzongsar Jamyang Khyentse Rinpoche which contained the following portion which I found helpful:

Rinpoche: Okay. Basically, as Buddhists, why do we meditate? It is to purify defilements and discover what they call Buddha nature? But when I say ‘Buddha nature’ I am not labelling this in terms of something good, something wholesome, something really beautiful, shining and so on and so forth. This I want to emphasis because if you are not careful with that, then the Buddhist concept of Buddha nature can be really misunderstood with concepts such as soul and atman and so on that many other religions talk about. ‘Buddha nature’ is a very beautiful name, ‘Bud-dha na-ture’. But that name is just a title or a name out of a lack of terms and names. We call it this but actually it's nothing to do with shining or divine or whatever.

I need to explain this. Let us use the glass windows here as an example. These glass windows are stained with dirt, so in our mind we think we should wash the windows. Now we are being very philosophical and quite intellectual here. In Buddhist philosophy they will disagree with that. They say you cannot wash the windows; you can only wash the dirt. The windows and the dirt that is stained on the glass are two separate entities. The glass, even though it has not been washed for millions of years, is just glass, it has not even heard what dirt is, right? Likewise aggression, passion and ignorance that we have are like dirt that is on the glass. They are not the real you. I'm just using very simple language here. So what we do is we try to wash the dirt. After washing the dirt then we realise that the glass becomes very clean. That is a standard understanding of nirvana, enlightenment. But then again Buddhists will dispute that because they will say, the glass has never become clean. Why? Because it was never dirty, right from the beginning. Glass is just glass; it has never been dirty therefore it cannot become clean. That quality is what we refer to as Buddha nature. We can even call it ‘Saddam Hussein’ if you want, it doesn't change anything. That quality is what we need to discover. Again the word ‘discover’ is very bad language but we have no choice.

So what we do with meditation is we try to clean this dirt. I guess when we finally reach there we will realise there was never any dirt. This is why I always say, from an emotional point of view, enlightenment is the ultimate boredom. I actually doubt how much we want this. I always discuss this with a lot of people. I mean, if you reach enlightenment and then suddenly you are omniscient right, you know the past, present and the future instantly. Then how are you going to enjoy a detective movie? So you will miss a lot of this.

I fled Him, down the nights and down the days; I fled Him, down the arches of the years; I fled Him, down the labyrinthine ways, Of my own mind; and in the mist of tears, I hid from Him, and under running laughter. Up vistaed hopes I sped; And shot, precipitated, Adown Titanic glooms of chasmèd fears, From those strong Feet that followed, followed after. But with unhurrying chase, And unperturbèd pace, Deliberate speed, majestic instancy, They beat - and a Voice beat - More instant than the Feet - ‘All things betray thee, who betrayest Me.’